The goal of this project is to develop a handheld, noninvasive, personal blood glucose-measuring device. VivaScan has developed and successfully tested several laboratory prototype instruments whose operation is based on the Optical Bridge(TM) method. It uniquely nulls out the background absorption of the tissue, overcoming the major problem of optical blood glucose measurements. Our successful Phase I laser instrument patient pilot study produced 97.5% of the measurement data in the clinically acceptable A and B zones of the Clarke error grid, with 70.4% of the measurements in the A zone, with an average measurement error of 19.8%. The aims for Phase II include: 1) develop a laser diode system light source; 2) enhance electronics; 3) redesign and miniaturize the optics and device mechanics; 4) design a handheld VS-200 system based on laser diodes, microcontroller, and miniaturized optical & mechanical components; 5) further enhance the glucose measurement algorithms; and, 6) build three handheld devices and test their performance with patients. Overall, the goal of the proposed work is to extend our laboratory prototype system to a patient oriented affordable device, integrate inexpensive laser diode light sources, improve accuracy, achieve portability, and ease of operation. Subsequent FDA approval of a handheld personal blood glucose monitor will be sought, allowing diabetic patients to noninvasively and painlessly monitor their glucose levels throughout the day. VivaScan and its partner NASA Goddard Space Flight Center believe that the current technology allows the fabrication of Tunable Laser Diodes (TLDs) with the desired wavelength of 1380 nm. This TLD is not commercially available since its center wavelength does not satisfy telecommunications requirements. It is proposed that a TLD, having the desired characteristics, be developed and incorporated into the VS-200 device.